To improve a data transmission throughput, dual connectivity supporting different access technologies, for example, multi-RAT dual connectivity (Multi-RAT Dual Connectivity, MR-DC) and long term evolution (long term evolution, LTE)-wireless local area network (wireless local area network, WLAN) interworking (LTE-WLAN interworking, LWI), is introduced.
FIG. 1 is a schematic diagram of a network with dual connectivity. As shown in FIG. 1, a terminal 01 may communicate with both a master node A and a secondary node B. The master node A and the secondary node B are connected to a core network C. Access technologies used for the master node A and the secondary node B may be the same or different. For example, the master node A is an evolved node (evolved universal terrestrial radio access network NodeB, eNB), and the secondary node B is a new radio node (new radio nodeB, gNB); or the master node A is a gNB, and the secondary node B is an eNB; or the master node A is an eNB or a gNB, and the secondary node B is a wireless local area network (wireless local area network, WLAN) device, where the WLAN device may be a WLAN termination (WLAN termination, WT), an access controller (access controller, AC), or an access point (access point, AP). The core network may be a 4G core network EPC, or a 5G core network (5G core, 5GC).
In the network in FIG. 1, a secondary bearer or a secondary split bearer may be established for the terminal 01. The secondary bearer may be referred to as a secondary cell group (Secondary Cell Group, SCG) bearer in MR-DC, and corresponds to an entire bearer that is moved to a WLAN side in LWI. The secondary split bearer may be referred to as a secondary cell group (SCG) split bearer in MR-DC.
For related content of MR-DC, refer to, for example, related content in Section 4 in 3GPP TS 37.340 V0.2.1. For related content of LWI, refer to, for example, related content in Section 22A in 3GPP TS 36.300 V14.2.0.
FIG. 2 is a schematic diagram of a secondary bearer. As shown in FIG. 2, a user plane connection between a core network C and a secondary node B is established for a terminal 01, and a user plane connection is established between the secondary node B and the terminal 01. When there is downlink data, the core network C sends all data of the bearer to the secondary node B, and then the secondary node B sends all the data of the bearer to the terminal 01. When there is uplink data, the terminal 01 sends all data of the bearer to the secondary node B, and then the secondary node B sends all the data of the bearer to the core network C.
FIG. 3 is a schematic diagram of a secondary split bearer. As shown in FIG. 3, a user plane connection between a core network C and a secondary node B is established for a terminal 01, a user plane connection is established between the secondary node B and the terminal 01, and a user plane connection is established between a master node A and the terminal 01. When there is downlink data, the core network C sends all data of the bearer to the secondary node B, the secondary node B sends a part of the data to the master node A, the master node A sends the part of the data to the terminal 01, and the secondary node B sends remaining data to the terminal 01. When there is uplink data, the terminal 01 may send a part of data of the bearer to the master node A, the master node A sends the part of the data to the secondary node B, the terminal 01 sends remaining data of the bearer to the secondary node B, and the secondary node B sends all of the received data of the bearer to the core network C. Optionally, it may be configured that the terminal 01 sends all data of the bearer to the master node A, and the master node A sends all the data of the bearer to the secondary node B; or it may be configured that the terminal 01 sends all data of the bearer to the secondary node B.
For the secondary bearer or the secondary split bearer, how to more precisely count a transmitted data volume of the bearer is a problem that urgently needs to be resolved.